Light metal cylinder head for internal combustion engines



Sept. 3, 1957 R oss 2,804,866

LIGHT METAL CYLINDER HEAD FOR INTERNAL COMBUSTION ENGINES Filed Nov. 28, 1955 2 Shee ts-Sheet 1 FIG. I

/NVENTOE Ecfdrd 7/085 @QAL Sept. 3, 1957 R. KLOSS 2,804,866 LIGHT METAL CYLINDEQ HEAD FOR INTERNAL COMBUSTION ENGINES Filed Nov. 28, 1955 2 Sheets-Sheet 2 Mil in IN VENTOR States LIGHT METAL CYLINDER HEAD FOR INTERNAL C'OIi/EBUSTHEN ENGINES Richard Kloss, Koindsuchforst, Germany, assignor to Kliickner-Humboldt- Dentz Akticngesellschaft, Kain, Germany The present invention relates to a cylinder head of light metal for internal combustion engines, especially diesel engines. More specifically, the present invention relates to a cylinder head of the above type which at its sealing surface is provided with a compression ledge directly resting against the sealing surface of the cylinder and tightly connected to the latter by means of bolts evenly distributed over the circumference of the cylinder head.

Compression ledges for sealing purposes are known. However, in their heretofore known form these compression ledges cannot be used as sealing means proper between-the cylinder head and the cylinder. With the heretofore known designs, the compression ledge is maintained as supporting element over its entire length even after the connecting bolts have been tightened. This arrangement has the drawback that the connection between cylinder and cylinder head is somewhat loosened following an operation of the cylinder. The reason for this consists in that during the operation of the cylinder heat stresses occur which bring about a further deformation of the compression ledge. When after completion of the operation of the cylinder the parts again cool down, there will exist a play between the cylinder head and the cylinder so that a leakage exists.

It is, therefore, an object of the present invention to provide a cylinder-cylinder head connection which will overcome the above mentioned drawbacks without requiring separate sealing means between the cylinder and the cylinder head.

It is another object of this invention to provide a cylinder head with a compression ledge for connection with a cylinder, in which the compression ledge will serve as highly satisfactory sealing means without requiring any additional gasket or the like.

These and other objects and advangtages of the invention will appear more clearly from the following specification in connection with the accompanying drawings, in which:

Fig. 1 represents a vertical longitudinal section through a lower portion of a cylinder head according to the invention and the upper portion of a cylinder of an air cooled diesel engine.

Fig. 2 is a view along the line II-II of Fig. 1.

Fig. 3 shows a cylinder head according to the invention connected to the cylinder after the connecting bolts have been properly tightened.

Fig. 4 is a modification over the arangement shown in Fig. 1.

General arrangement The cylinder head according to the present invention provided with a compression ledge for engagement with the sealing surface of the cylinder is characterized in that the compression ledge is so dimensioned that within the range of the connecting bolts the compression ledge is completely flattened by the tightening force of the bolts so that the entire sealing surface of the cylinder head within the range of said bolts bears against the sealing surface of the ater cylinder. In other words,-when the connecting bolts are tightened the cylinder head so to speak fully sets on the sealing surface of the cylinder. Within the range of the connecting bolts the bearing surface of the now flattened compression ledge is so great that a deformation during the heating of the cylinder and cylinder head will be excluded. In the central portion between two connecting bolts, the deformation of the compression ledge is smallest. This is due to the fact that the cylinder head is not a completely bend-resistant unit. The bending of the cylinder head in the central portion between two connecting bolts is the reason why the deformation of the compression ledge outside the range of the connecting bolts becomes less with increasing distance from said bolts. The deformation is such that between the compression ledge and the sealing surface of the cylinder all the way around a substantially even specific pressure load occurs which remains also after the cylinder and cylinder head heat up.

In order to prevent a clamping along the collar of the cylinder due to the compression ledge giving way toward the sides, according to a further development of the invention the compression ledge is so aranged 011 the'sealing surface of the cylinder head that within the range of the connecting bolts there will still remain a sealing surface of the cylinder at both sides of the compression ledge.

Instead of providing one annular compression ledge, also a plurality of smaller annular compression ledges may be provided in spaced relationship with regard to each other.

Structural arrangement against the cylinder 2 without any gasket or other separate sealing means therebetween. The cylinder head 1 is connected to the cylinder 2 in a manner known per so by connecting bolts 3 extending through bores 3a in the cylinder head. The cylinder head 1 is provided with a compression ledge 4 by means of which it rests against the sealing surface 5 of'the cylinder 2. The compression ledge is so dimensioned that when the bolts 3 are tightened, the compression ledge will completely flatten within the range of the bolts 3 so that the entire sealing surface 9 of the cylinder head will bear. According to tests, a compression ledge having a height of .2 millimeter has proved highly satisfactory with cylinders having an inner diameter of approximately 110 milimeters and an ignition pressure of from to 90 atmospheres above atmospheric pressure. The connecting bolt tension should amount to about 1.5 to 3 times the ignition pressure multiplied by the piston surface and divided by the number of the connecting bolts. Assuming for instance a bolt tension of 2 /2 times the ignition pressure of atmospheres above atmospheric pressure, a connecting bolt force of about 5250 kilograms will be obtained. The compression ledge according to the invention is so to be dimensioned that for instance at the said connection bolt pressure the compression ledge will completely flatten within the range of the connecting bolts so that within the range of said bolts the entire sealing surface of the cylinder will .bear. With a connecting bolt force of 5250 kilograms and a hight of about 0.2 millimeter of the compression ledge, the width of the latter is about 5 millimeters. J

In Fig. 2, the solid lines 6 indicate the width of the compression ledge prior to the first installation of the cylinder head without any load exerted by the connecting bolts 3. However, when the bolts 3 are tightened; the compression ledge will deform along the dot dash line '7 of Fig. 2; The course of the dot dash line 7 shows that the compression ledge 4 is within the range of the connecting bolts deformed more than in the central portion between two adjacent bolts 3. Within the range of the connecting bolts, the compression ledgeis deformed ,to such an extent, as mentioned above that the entiresealing surface 9 of the cylinder head will bear within the range of the connecting bolts 3. 7 i

In order to preventthecylinder head 1 from clamping itself against the collar8 of the cylinder due to'the lateral give-way of the compression ledge 4, the compression ledge 4 is arranged over a portion only of the width of-the sealing surface 9 of the cylinder head 1. The compression ledge 4 is so distributed over the sealingfsurface 9 that a portion of the sealing surface 9 will remain at both sides of the compressionledge.

The embodiment shown in Fig. 4,diifers from that of Figs. 1 and 2 in that the compression ledge 4 of Fig. 1

has been replaced'by two smaller compression ledges 10,

It is, of course, understood that the present invention is, by no means, limited to the particular construction shown in the drawings but also comprises any modifications within the scope of the appended claims.

What I claim is:

1. A cylinder head of light metal for connection by connecting belts with cast iron and steel cylinders of internal combustion engines, said cylinder head having'a sealing surface arranged for engagement with a corresponding surface of a cylinder and provided with a circular comnecting bolts a portion of the said sealing surface remains at both sides of said compression ledge following the flattening thereof.

3. A cylinder head of light metal for connection by connecting bolts with cast iron and steel cylinders of internal combustion engines, said cylinder head having a sealing surface arranged for engagement with a corresponding surface of a cylinder and provided with a plurality of circular compression ledges arranged in spaced relationship to each other and so dimensioned that said compression ledges Will completely flatten within the range of said connecting bolts in response to said connecting bolts being tightened to such an extent that the screw tension equals approximately from 1.5 to 3 times the ignition pressure multiplied by the inner diameter of said cylinder and divided by the number of connecting bolts.

4. A cylinder head according to claim I, in which the compression ledge has a height of approximately .2 millimeter.

5. A cylinder head of light metal for connection by connecting bolts with cast iron and steel cylinders of internal combustion engines, said cylinder head having a sealing surface arranged for engagement with a corresponding sealing surface of a cylinder and provided with a compression ledge for directengagement with the sealing surface of said cylinder, said compression ledge 'being dimensioned to completely flatten within the range of said connecting'bolts when the latter are fully tightened therebycausing the entire sealing surface of the cylinder head within the range of said connecting boltsto bear against the sealing surface of said cylinder.

References Cited in the file .of this patent UNITED STATES PATENTS 306,293 Tennant et a1. Oct. 7, 1884 757,376 Whitaker Apr. 12, 1904 1,825,769 Barbarou Oct. 6, 193.1 2,553,222 Wallgren et al, May 15, 19:51

I A FOREIGN PATENTS 122,377 Australia Oct. 6, 1944 832,520 Germany Feb. 25,, 1952 

